At 529, Egypt has sentenced an unprecedented number of Muslim Brotherhood supporters to death. They’re supporters of Mohamed Morsi, Egypt’s first democratically elected president ousted by the military in July.

Cairo — In what appears to be the largest such mass sentencing in modern times, an Egyptian court has convicted 529 people of capital crimes, a move that has stunned human rights defenders who decry deep systemic biases in the country's politicized judiciary.

The defendants are all accused of belonging to the Muslim Brotherhood, which held power until last July and has since been outlawed and labeled a terrorist group. The court convicted them today of involvement in an attack on a police station in Minya last Aug. 14 that left one policeman dead. It came on the same day as a bloody crackdown by police on a protest camp in Cairo that killed hundreds and which Egypt's new rulers continue to defend as just. Editor's note: This paragraph has been edited to correctly reflect the defendants' connection to the Muslim Brotherhood.

While legal experts say that the sentences are likely to be overturned on appeal, rejected by Egypt’s grand mufti, or commuted by the president, the rulings drew stinging criticism from both domestic and international rights groups.

Mohamed Zaree, director of the Cairo Institute for Human Rights Studies, said he had not witnessed a verdict of such severity or magnitude during the course of his entire career. “It’s the worst verdict we’ve seen in Egyptian history,” he said. “It’s a legal massacre."

Family members stood outside the courthouse screaming after the verdict, a reminder of the deep divisions that have plagued Egypt since the overthrow of President Mohamed Morsi, a Brotherhood leader. Many of those convicted today were tried in absentia; around 150 were in the courtroom. The charges against them included murder, attempted murder, and stealing government weapons.

Egypt rarely issues the death penalty, even during periods of political repression. Between 1992 and 2001, when former President Hosni Mubarak led a crackdown, only 94 people were sentenced to death. The rate has increased since the 2011 revolution, but rights groups say it remains unclear whether any sentences have been carried out.

Defense lawyers say that the Minya case was riddled with violations in due process, and claim that many of the condemned were charged as a result of personal vendettas between individuals and policemen.

Ahmed Shabeeb, one of the lawyers, says his team wasn't given time either to review the evidence or to cross-examine prosecution witnesses. The trial opened Saturday; today was the second and final session.

Widening crackdown

Although unprecedented in scale, Monday's mass verdict points to a broader set of legal failings in the Egyptian penal system. As Egypt's military-backed government has tried to erase Mr. Morsi's movement from political life, these failings have been brought to the fore. Authorities have also cracked down on secular dissidents who rose to prominence during the revolt against Mr. Mubarak and don't share the Brotherhood's Islamist politics

According to state officials, around 16,000 people have been arrested since July 3. An independent count by Cairo-based rights group the Egyptian Centre for Economic and Social Rights puts the figure at closer to 24,000.

The Muslim Brotherhood have repeatedly criticized Egypt’s judiciary for a string of harsh and seemingly politicized decisions. In a statement Tuesday it condemned the Minya trial as a “kangaroo court, [reinforcing] the junta's message.”

But others note that Egypt’s judiciary has long bent to the will of the nation's political masters and come down hard on those who appear to threaten the institutions of state, regardless of who is in power.

“The judiciary as a whole seems to have reacted with fear and loathing to Brotherhood rule, but different courts have behaved quite differently so it is difficult to discern any overall intentions,” says Nathan Brown, a professor at George Washington University who has written extensively on the Egyptian legal system.

Legal precedent

Hundreds of other suspects are due to be tried on Tuesday in a second mass trial in Minya, among them the Brotherhood’s Supreme Guide Mohamed Badie. The severity of today's rulings raises concern that a precedent has been set for future trials of dissidents.

Morsi is also subject to ongoing trial proceedings in four separate cases being judged in a courtroom outside Cairo. If found guilty, he could also face the death penalty, although legal experts predict that this is unlikely, given the potential international fallout.

Whatever the final verdict in the Minya case, rights groups point to persistent violations in Egypt as the military-backed government forges ahead with its crackdown.

“Mass trials are taking place on an almost everyday basis,” says Sarah Leah Whitson, the Middle East Director at Human Rights Watch. “In many cases we are seeing the failure of courts to allow defendants to present their case, a failure to call witnesses, and a failure to assess the individual culpability of each defendant.”

“It was only a matter of time before one of these mass charges ended in this way,” she said. “It shocks the conscience and represents a serious miscarriage of justice.”